Web browsers were originally designed as user-friendly portals to the internet's resources that facilitated internet navigation and information search, but have since evolved into more sophisticated and complex software applications. Web browsers now incorporate sophisticated multimedia rendering functions (video, audio, imaging, etc.) and enable a user to navigate and interact dynamically with connected websites and other internet users.
Uniform resource locators or URLs are the addresses of internet resources on the World Wide Web, e.g., a webpage that is on a website. A prefix to the URL is a Uniform Resource Identifier (URI) which specifies how the URL is interpreted. A common URI contains a character string “http” which identifies the URL as a resource to be retrieved over the Hypertext Transfer Protocol (HTTP). Other common prefixes are “https” (for Hypertext Transfer Protocol Secure), “ftp” (for File Transfer Protocol), and “file” (for files that are stored locally on a user's computer). If a URL points to a website, which is often a case, the web browser uses the URL to access the website and retrieve the webpage from the website.
Once the webpage has been retrieved the web browser will display it. Hypertext Markup Language (HTML) documents and any associated content (text, images, video, audio, etc.) are passed to the web browser's layout engine to be transformed from markup to an interactive document, a process known as “rendering.” Webpages frequently include other content such as formatting information (e.g., Cascading Style Sheets) and scripts (e.g., JavaScript) into their final presentation.
Webpages have progressed from static pages to full-blown user customizable applications. A web application is a computer software application that is coded in a web browser-supported programming language (e.g., HTML or JavaScript) and reliant on a common web browser to render the application executable.
With the constant emergence of new webpage technologies, such as HTML 5, not all web browsers are able to render content as originally intended by the website's author. In addition, many web browsers rely on plug-ins to display web content properly. Consequently, websites will function and display differently based on the content rendering capabilities of the web browser.